Machines are used to erect end loading sleeve type cartons from a flat, collapsed configuration to an open configuration in preparation for loading with products. These machines employ hoppers which contain stacks of cartons in their flat, collapsed configurations. The cartons are sequentially moved to a position within the hopper where the carton erecting machinery may grasp them to initialize the erection process.
Typically, these hoppers have been oriented uprightly so that each carton may gravitate into position for extraction as shown in U.S. Pat. Nos. 5,019,029 and 5,176,612. To reduce the frequency in which the hopper must be loaded, a large stack of cartons is typically loaded at once. As large stacks are oftentimes loaded upon previously loaded cartons, a person loading the hopper must be elevated well above the machinery to accomplish this task with its attendant risk of personal injury. In addition to the risk of injury, the combined weight of the cartons upon the bottommost carton often makes it difficult to be grasped and removed readily.
To alleviate these problems conveyor belts have been employed which load the hopper with cartons at the same rate at which they are extracted. The cartons are typically placed on the conveyor so as to overlap or "shingle" each other. However, rough surfaces of some cartons or the end flaps of overlapping cartons often causes them to interlock which in turn cause them to be improperly or only partially loaded into the hopper.
It thus is seen that a need remains for a machine for erecting sleeve type cartons in a safer, more efficient and reliable manner. Accordingly, it is to the provision of such an improved machine that the present invention is primarily directed.